BUFFON. 137 



Buffon not only saw the negative influences of 

 environment in the reduction of numbers and in 

 the reduction of imperfect types, but also its posi- 

 tive action in the production of new characters, and 

 here we come upon the third and main feature of 

 what may be called his theory of the factors of Evo- 

 lution ; namely, the direct action of environment in 

 the modification of the structure of animals and 

 plants and the conservation of these modifications 

 through heredity. He applied this factor to the 

 origin of new species in the New World of Amer- 

 ica. It is amusing to the modern zoologist to note 

 that Buffon, in common with all his contemporaries, 

 always conceived of the New World as not only 

 new in point of discovery, but as new in its zoologi- 

 cal evolution. He illustrated his ideas as to the 

 direct action of environment in saying that Old- 

 World types, finding their way into the New World, 

 would there undergo modifications sufficient to cause 

 us to regard them as new species ; and in this con- 

 nection Buffon expresses the uniformitarian idea 

 which Lamarck carried to such an extreme (which 

 was opposed to his general cataclysmal teaching, 

 that Nature is in a continual state of transition) ; 

 namely, that man must consider and observe 

 changes which are going on in his own period in 

 order to understand what has gone on in the past, 

 and what will happen in the future. 



It is with such passages as these that Buffon 

 inspired later writers to consider the great problem. 



